Toggle switch construction



8, 1957 E- L. BARRETT 2,794,086

TOGGLE svmcn CONSTRUCTION Filed June 9, 1954 United States Patent TOGGLESWITCH CONSTRUCTION Edward L. Barrett, La Grange, 1ll., assignor to Barrett- Keenan Company, Chicago, 111., a copartnership Application June9, 1954, Serial No. 435,455

Claims. (Cl. 200--67) The present invention relates to switches and moreparticularly to toggle switches for use in aircraft or the like. 7

It is an object of the present invention to provide a toggle switchwhich has a high degree of reliability and which is capable of carryingcurrents which are substantially higher than those carried by ordinarytoggle switches of comparable size. It is another object to provide atoggle switch which has extremely low contact, resistance and whichmaintains such low resistance over a long period of use, even in theface of extreme shock and vibration. It is a further object to provide atoggle switch which has a voltage rating higher than the rating ofconventional switches in the same size classification and which iscapable of safely cutting off current flow even under short circuitconditions.

It is another object of the invention to provide a toggle switch whichis sealed against entry of dirt and moisture but which is neverthelesseasily operated and which provides positive detent action.

Finally it is an object to provide a toggle switch which is inexpensiveto construct, which may be quickly and securely mounted and whichrequires no care or maintenance.

Other objects and advantages of the invention will become apparent uponreading the attached detailed description and upon reference to thedrawing in which:

Figures 1, 2 and 3 are side, front and rear elevations respectively of atoggle switch constructed in accordance with the present invention.

Figure 4 is a vertical section of the toggle switch shown in Figure 1.

Figure 5 is a horizontal section taken along the line 55 in Figure 4.

Figure 6 is an exploded perspective showing the rocker and associatedparts.

Figure 7 is a fragmentary section taken through one of the rocker armsand showing the contact construction.

Figure 8 shows in perspective a mounting ferrule prior to assembly ofthe switch.

Figure 9 is an exploded fragmentary perspective of a modified rocker andcarrier.

While I have described in the attached specification and shown in thedrawing only certain preferred forms of the present invention, it willbe understood that I do not intend to limit myself thereto but intend tocover all other modifications and alternative constructions fallingwithin the spirit and scope of the appended claims.

Turning now to the drawing, the switch indicated generally at 20 has abody 21 which is formed of molded plastic material having high strengthand dielectric properties. The body is of hollow, rectangularconstruction having a bottom wall 22 and having integral end portions23, 24. The body is closed by a face plate 25 which has a rectangularoutline as shown in Figure 2 and which is secured permanently to thebody 21 by means of hollow threaded ferrules 31, 32. Such ferrulesareice spun over at their ends as indicated at 31a, 32a, respec tively.

Mounted in the face plate 25 for rocking movement is a switch lever orhandle 35 having a ball enlargement 36 at its inner end. For the purposeof mounting such ball for rocking movement, the face plate 25 has asocket 37 integrally formed therein and which has an elongated slot 38.Fastened to the face plate 25 is a backup plate 40 having acorresponding socket 41 integrally formed therein so that the ballenlargement on the operating handle is held captive between them. Theface plate 25 and the backup plate 40 are permanently fastened togetherby rivets 43, 44. Sandwiched between the two plates is a rubber gasket46. Such gasket serves several functions, the edge portion serving toseal the joint between the face plate 25 and the body 21 while thecenter portion thereof snugly embraces the ball 36 on the switch handleas shown in Fig. 4. This is accomplished by making the clearance hole atthe center of the gasket slightly smaller in nominal diameter than thediameter 'of the ball 36. Preferably the face plate has integrallyformed bosses 48, 49 which not only recess the heads of the rivets 43,44 but which also insure that the plates 25, 40 are accurately spacedrelative to one another, insuring free pivoting movement at the ball andsocket joint.

In carrying out the present invention, contacts 51, 52 are provided inthe bottom wall of the switch body cooperating with a pivoted rocker orrocker plate 53 which extends longitudinally within the body havingcontact assemblies 55, 56 mounted thereon. The rocker is mounted upon arocker carrier 54 which engages the center of the rocker 53 for limitedtilting movement of the latter. Prior to discussing the details ofconstruction of the rocker carrier 54, more specific reference will bemade to the means for tilting the rocker back and forth. This functionis provided in the present instance by a detent plunger 60 having asperical end 61 which rides along a longitudinal path on the back of therocker 53. The detent plunger 60 is received in a bore 62 in the switchhandle. To press the plunger outwardly a coil spring 65 is used bottomedin the bore 62. It will be apparent that the spring pressed plunger 60performs a detenting function as the end 61 thereof moves from one sideto the other of the central pivot on the rocker 53.

In accordance with the present invention a novel selfleveling contactassembly is employed at each end of the rocker 53 for engaging thestationary contacts 51, 52. The contact assembly 55 will be taken asrepresentative, being detailed in Figures 6 and 7. The movable contact,indicated at 70, has a spherical surface 71 which is received in aspherical socket 72 to provide a ball and socket joint. For the purposeof retaining the contact in the socket and for resiliently clamping itto the end of the rocker, a spring retaining washer 73 is used which ismounted at the end of an integral shank 74 which extends rearwardly fromthe contact and through a clearance opening 75 formed in the center ofthe spherical socket. The spring washer 73 is preferably of spidershape, having resilient downwardly bent legs 74a, each of which isreversely bent to ride smoothly on the outer surface of the socket 72.The upper surface of the socket, indicated at 76, is concentric with thesocket surface 72 so that the spring washer 73 may ride through arelatively large are in any direction without binding and with notendency to depart from any given position of adjustment. Preferably,the washer 73 is in tight engagement electrically and mechanically withthe contact 70, the washer being held in place by spinning over the tipof the shank 74 as shown. The legs of the washer 73 may be preloaded bybending them downwardly be- Patented May 28,

fore the contact assembly is put together in order to establish adequatesqueezing pressure on both the inner and outer surfaces of the socket72. With the contact assembled ,as described, it is found that thecontact-torock er resistance is maintained at an extremely low valueindependently of the pressure which may be exerted by the cooperatingstationary contact 51 and independently of its orientation.

The self-leveling action of the. above structure is clear ly shown inFigure 7 which illustrates the initial closure. The first time that thecontacts are snapped together by the switch handle, the movable contact70 is in a random position resulting in edge engagement as shown at 78.However, because of the downward pressure on the rocker exerted by thespring 65 and because of the inertia of the rocker 53 the movablecontact moves in its socket, adjusting itself precisely to the uppersurface on the fixed contact 51. The friction produced by the springwasher 73 is suificient to hold the movable contact in such position sothat'fiat face-toface contact occurs during all subsequent switchoperations.

It will be apparent that if either contact surface is eroded as a resultof severe use, constant equalization of the contact 76 will occur,always insuring that the maximum available contact area is used andinsuring that the resistance will continue to be low over the life ofthe switch. In the event that the movable contact is jarred from itsoptimum position by shock or severe vibration, it will be restored tosuch condition when it' is closed the next time. While the abovediscussion has been restricted to the contact assembly 55 it will beunderstood that it is equally applicable to the identical con tactassembly 56 at the other end of the rocker.

Having understood that contact structure afforded in the present switchmore specific attention may be given to the novel means for pivoting therocker 53. In accordance with the present invention pivoting of therocker and lateral centering thereof is accomplished by using opposedball and socketjoints laterally spaced at the center of the rocker. Asillustrated in Figures 5 and 6 the ball and socket are formed integrallyon the rocker carrier 54 and rocker 53' respectively. The rocker carrier54 is of U shape having upwardly extending arms 81, 82 which are locatedadjacent the side Walls of the switch body. Each of the arms is inwardlydimpled or deformed to provide opposed balls 83, 84 respectively.

For the purpose of accurately locating the rocker carrier 54 a recess isprovided in the bottom wall of the switch body (see section Figure 4). Acorresponding recess is formed on .the outside wall for receiving aterminal 85', the carrier 54 and terminal 85 being engaged by a rivet 86which extends through both of them and which secures them togetherelectrically and mechanically.

Cooperating sockets are integrally formed onthe lateral edges of therocker 53. Eachof the sockets. is in the shape of a quarter-spherehaving the same curvature as the balls to provide a joint which islargely friction free but which has appreciable area in contact. Sincethe sockets 87, 88 are relatively deep and since constant springpressure is applied to the rocker by the plunger 60, there is no riskthat the rocker will be moved out of register with the balls even in theface of severe shock. It will be noted, in any event, that the limitedendwise clearance of. the-rocker with respect to the switchbody and thelimited. sidewise clearance between the rocker and the carrier 54insures that the rocker will always return to a seated position; ,Use ofopposed and laterally spaced ball and socket joints limits the rocker topure rocking movement in a centered position, and it is impossible forthe rocker to skew or to ride up into engagementwith one of the arms ofthe rocker carrier 54. The above construction insures accurate registrybetween the fixed and movable contacts and therefore maximum use of theavailable contact area.

If desired, the arms of the rocker may bebent upwardly on each side ofthe central pivot to provide a slightly curved track for the end of theplunger 60. Such curvature furthermore increases the distance betweenthe contacts when in open position. However, in order to provide strongdetenting action and to reduce the required head room in the switchbody, the curvature is preferably kept to a small amount.

For the purpose of positively anchoring the fixed contacts 51, 52, eachof them is provided with shanks 91, 92 respectively which are riveted toterminals 93, 94. Such terminals have a base portion which lies flatlyagainst the molded body. Positive location of the terminals as well aselectrical isolation is provided by barriers 95, Q6.

It will be apparent to one skilled in the art that the invention is notlimited to providing sockets on the rocker 53 and if desired theposition of the balls and the sockets may be reversed as shown in themodified structure of Figure 9. Here the rocker indicated at 53a isdeformed along its lateral edges to provide downwardly extending ballsurfaces 87a, 88a. The rocker carrier indicated at 54a iscorrespondingly deformed along its lateral edges to provide integralspherical sockets 83a, 84a, the surface radius of the balls and socketsas well as the spacing between them, being the same. Such structureenables smooth rocking movement of the rocker 53a, the opposed ball andsocket joints serving, as in the previous embodiment, to prevent skewingof the rocker while maintaining the rocker in its desired centeredposition. The latter embodiment may be preferred where it is desired toreduce the manufacturing cost to a minimum since tolerances are moreeasily maintained.

In accordance with one of the more detailed aspects of the presentdevice the threaded ferrules 31, 32 which hold the face plate inposition on the switch body include a novel means for anchoring on theswitch body and for securely locking a mechine screw used to hold theswitch to a panel. For this purpose the ferrules, 31 being taken asrepresentative, include a rectangular base 97 which is snugly recived ina recess 98 formed in the switch body and which is slotted to receive aninsert 99 formed of fiber or the like. Such insert is pierced and thefree opening provided therein is smaller than the diameter of themachine screw so that the machine screw is jammed in place and cannotwork itself loose as a result of continued vibration.

It will be apparent from the foregoing that a switch is provided whichis of eminently simple and inexpensive construction but which includesfeatures which are not to be found in conventional toggle switches. Itwill be noted that when the rocker is in one of its seated positions itis stably supported at three areas which are arranged in triangularformation. Each of such areas comprises a ball and socket in whichrubbing friction is low but which, nevertheless, provides a substantialarea over which current flow may take place. As a result the contactresistance from terminal to terminal may be reduced to a minimumenabling the switch to operate cool even under rather extreme loadconditions. Should the contacts become eroded as a result of continuedsevere use, automatic and constant self-alinement occurs, each movableswitch contact reorienting itself to engage maximum contact area on thefixed contact. It is also found that excess voltages may be successfullyinterrupted without undue arcing and without damaging the switch.Preferably the switch body is formed of a number of plastics having goodarc resisting. characteristics. Arcing to the casing, common in switcheshaving metal bodies, is precluded in the present construction. Leakageresistance under humid conditions is reduced to a minimum. As a resultof the above. features the present toggle switch is ideally suited foruse in aircraft or for use for military purposes where high performanceand absolute reliability are essential.

While the invention has been described above as embodied in a toggleswitch, it wll be apparent to one skilled in the art that certain of thefeatures of constructtion are not at all limited to use in toggleswitches but would have more general utility wherever it is desired toprovide self-alining contacts having extended contact area and whereverthe making of contact is brought about by application of force generallyperpendicular to the contact faces. By the term laterally spaced balland socket joints is meant joints comprising concave and convex portionsin nesting engagement providing a substantial contact area whilepermitting limited rocking movement and preventing any axial movement orskewing.

I claim as my invention:

1. In a toggle switch the combination comprising a switch body having aswitch contact located at the bottom thereof, a rocker plate arrangedgenerally parallel to the bottom of the switch body, said rocker platehaving a movable contact mounted on an end thereof, a rocker supportingmember mounted at the bottom of said switch body and spaced from thefixed contact, the rocker plate and the rocker supporting member beingdeformed to provide mating curved surface connections at the lateraledges thereof having a substantial area in contact for permittinglimited rocking movement of the rocker plate while blocking the rockerplate against axial movement, and switch operating means movable betweenan on position and an off position and having a spring biased member forexerting downward pressure on said rocker plate when in the on positionat a point centered between the pivot axis and the movable contact sothat pressure is exerted simultaneously at said contacts and at said connection to minimize the contact resistance thereof.

2. In a toggle switch the combination comprising a switch body having afixed contact flatly seated therein, a rocker plate in said switch bodyarranged generally parallel to said fixed contact, said rocker platehaving a movable contact at one end thereof arranged opposite said fixedcontact, a rocker supporting member seated in said switch body under thecentral portion of said rocker plate and having lateral edges extendingclosely adjacent the edges of said rocker plate, the lateral edges ofsaid rocker plate and said rocker carrier being of such shape as toprovide laterally spaced ball and socket joints for limiting rockingmovement of the rocker plate on the rocker carrier, said switch bodyhaving a face plate, a toggle lever mounted in said face plate forrocking movement about an axis parallel to the rocking axis of therocker plate, said toggle lever having a central bore, a plungerreceived in said bore, means including a coil spring for urging theplunger outwardly of said bore and into contact with said rocker plateso that when said toggle lever is in one of its limit positions theplunger applies pressure to the rocker plate at a point located be tweensaid movable contact and said ball and socket joints thereby to maintainthe ball and socket joints in engagement and to minimize the contactresistance thereof.

3. In a toggle switch the combination comprising a switch body, at fixedcontact flatly mounted in said switch body, a rocker plate in saidswitch body arranged generally parallel to the fixed contact, a rockercarrier centrally mounted in said switch body and extending transverselywith respect to said rocker plate, said rocker carrier and said rockerplate being deformed to provide mating curved surface connections at thelateral edges thereof having a substantial area in contact forpermitting limited rocking movement of the rocker plate toward and awayfrom said fixed contact while blocking the rocker plate against axialmovement, a movable contact mounted on said rocker plate opposite saidfixed contact said movable contact having a ball and socket connectionwith the rocker plate and having means for resiliently maintaining themovable contact seated on said rocker plate when the contacts areseparated from one another, and manually operated means including abiased member for ap resilient pressure to a point on said rocker platewhich is centered between the ball and socket connection and the twopivoting connections for simultaneously pressuring the contacts and thepivoting rocker plate supports.

4. In a toggle switch the combination comprising a switch body, a fixedcontact in said switch body, a rocker in said switch body arrangedopposite the fixed contact, a rocker carrier mounted in said switch bodyand extend ing transversely at the central portion of said rocker, saidrocker carrier and said rocker being deformed to provide mating ball andsocket connections between them which are laterally spaced from oneanother so that the rocker plate is confined to limited pure rockingmovement toward and away from said fixed contact, a movable contactmounted on said rocker opposite said fixed contact, said movable contacthaving a ball and socket connection with the rocker and having means formaintaining it seated on said rocker when the contacts are separatedfrom one another, and manually operated means for applying resilientpressure to a point on said rocker which is centered between the threeball and socket connection for bringing said contacts into engagement.

5. In a toggle switch, the combination comprising a hollow switch bodyhaving one open wall, a rocker carrier recessed in said body, a rockerin said body in said carrier, said rocker and carrier having a pair oflaterally spaced ball and socket connections for permitting rockingmovement while preventing axial and skewing movement, contacts withinsaid switch body at the ends thereof for cooperating with said rocker, aface plate to cover said open wall and having means permitting it to bese cured to said body, a switch lever extending through said face plateand having a bail portion intermediate its ends, a back-up plate securedto said face plate, said plates being apertured and deformed to snuglysocket said ball portion and thus pivotally support said lever, and agasket positioned between said plates to extend between said face plateand body, said gasket being apertured to sealingly engage said ballportion of said lever, the lower end of said lever being in contact withsaid rocker for over-center rocking movement of the latter.

References Cited in the file of this patent UNITED STATES PATENTS1,604,154 Erskine Oct. 26, 1926 1,753,975 Welsh Apr. 8, 1930 1,892,008Ross Dec. 27, 1932 1,918,282 Meuer July 18, 1933 2,222,843 Ives Nov. 26,1940 2,377,134 Dietrich May 29, 1945 2,432,647 Batcheller Dec. 16, 1947FOREIGN PATENTS 592,084 France Apr. 23, 1925 213,316 Switzerland Feb.22, 1940

